Point 9 of my 12 point list of methods for reducing cracking
in

portland cement stucco

An ounce of prevention is worth 3,000 lbs.
of cure. Whole wall is stripped down to block.
This assures a nice job. Patches almost always show.

The culprit was this roof cap. Water runs
right down the cove in the cap and gets behind the stucco.

Bottom cap is removed and pushed under
the upper cap. The overlap prevents water infiltration.
This would have been prevented
if the bottom piece was put on first, 30 years ago.

Protecting the work after it's finished is out of the
control of the plasterer. All I cando is insist that things like roof caps are done, but I
don't put them on.The material we work with lasts pretty much forever, as
long as water doesn't run behind the wall.This example of a block wall is bad enough. Wood framed
walls require moreattention. If the wall isn't capped immediately after
the stucco is finished,water infiltration can cause warping of the framing
lumber, cracking the stucco.
Badly spalled block and stucco wall will have a new roof cap when we
replace the stucco.

We put on a kick out flashing to
divert water into the gutter.
Not beautiful, but it keeps water
from running behind the wall.

All horizontal members on tudor style
stucco should be flashed , like
over windows, before the metal lath
goes on.